The invention relates to a clamping assembly mounted on one of opposed stationary and movable platens of an injection-moulding machine for clamping a die half of a die for injection-moulding a product, and of that kind which is arranged to be adjusted to receive die halves of various sizes.
The material to be moulded is typically a thermoplastic plastic, which in a heated liquefied or plasticized state, is injected into the die. The die halves of the die are clamped upon their respective opposite platens of the injection-moulding machine to be used. One of the platens is stationary while the other one is movable between a position, in which the die is closed and a position, in which the die is open. The die is, during operation, cooled for bringing the hot injected plastic into its solid state. The die is then opened and the product ejected.
A specific injection-moulding machine in an injection-moulding plant is frequently used for dies of various sizes. The dies must however, irrespective of their size, fit to the platen of such a machine. This fact implies that some dies need to have an unnecessarily large size in proportion to the size of the product to be moulded, thereby causing extra costs for producing the dies.
Over the years attempts have been made to overcome this problem.
A frame for clamping dies for moulding more products at the same time is for example known from the patent publication U.S. No. 2004/0001901 A1. In this case a die is built up of more parts which are arranged in a module system and together fit the frame. The frame is not adjustable and cost saving is only possible for products in such module system.
The U.S. Pat. No. 4,500,275 describes a flexible clamping assembly for clamping dies of various sizes by means of retainer clamps and screw devices for screwing the retainer clamps into intended positions in relation to the platen of the injection moulding machine used. The clamping device is however
difficult and time-consuming to adjust. The mounted die can moreover not be securely and exactly retained and positioned. To this may be added that it is only possible within narrow limits to adjust this known clamping assembly.
Japanese Patent Application No. JP 56 155731 is concerned with relocating of die-assemblies by using a die-transferring truck. Each die half is mounted on a fitting plate which in turn is clamped onto a corresponding fixing plate.
Japanese Patent Application No. JP 2005 186146 discloses a die-fastening device comprising a frame-shaped jig which is attached to a platen. Onto the frame-shaped jig are mounted two die base supporting blocks that feature hackers and pins for fastening the a die.
UK Patent Application No. GB 2 274 424 discloses a device for tool changing, the device comprising guide means and a stop which are used for correctly positioning a backplate attached to a die half onto a platen. The device further features clamp members that are mounted on carriers, which in turn are fastened to the platen. A die half may be introduced by fastening it to a backplate, guiding said backplate through the guiding means and fastening the backplate to the platen by using the clamping members.
Japanese Patent Application No. JP 2003 071898 provides a cooling structure for a mold comprising a cylindrical cooling tube and conduits for supplying coolant to the cooling tube.
European Patent Application No. EP 0 555 976 discloses a metal mold cooling device comprising a cooling hole into which a cooling pipe may be inserted which is capable of cooling liquid transfer into the cooling hole. The cooling liquid may be discharged through a discharge pipe.
The devices of these references all suffer from deficiencies such that a need exists for improved devices.